Motor performing vector control in a start mode
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Solution Overview
Problem
Washer motors experience noise and vibration issues during start-up due to the 120° current application method, leading to system instability, and inaccuracies in power application with the 180° method, causing motor stoppage or increased noise, especially during washing and rinsing cycles.
Innovation Solution
Implementing a 180° current application method with vector control using a d-q axis rotating coordinate system and a motor controller with a speed/position detector and PWM calculator to accurately control current and voltage, ensuring continuous rotor position assumption and reduced noise/vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the 120° current application method is used during start mode, then the motor can be driven with a general position of the rotor, but it generates overcurrent and produces large noise and vibration due to torque ripple
Solution Approach 1:
The patent changes the current application parameters by switching from 120° to 180° conduction mode during start-up. This parameter change eliminates the power non-application region, providing continuous torque and eliminating torque ripple, thereby reducing noise and vibration while maintaining ease of starting operation.
2Object-generated harmful factors
If the 180° current application method is used, then the system operates stably with reduced noise, but the motor may stop or noise increases when rotor position is inaccurately measured
Solution Approach 1:
The patent applies preliminary action by using the 180° current application method specifically during the start-up mode before switching to 120° mode for normal operation. This preliminary application of the more stable control method during start-up ensures accurate rotor position control is established before transitioning to the simpler 120° mode, preventing motor stoppage while maintaining low noise.
3Ease of operation
If the 120° current application method is used during start mode, then the motor can start with general rotor position, but the system becomes unstable and generates overcurrent
Solution Approach 1:
The patent changes the operational mode parameter from 120° to 180° current application specifically during start-up. This parameter change provides continuous power application to all phases, eliminating the instability and overcurrent issues associated with the 120° method's power non-application regions, while still allowing the motor to start with general rotor position.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables low noise and vibration operation even during start-up, improved power control, and prevention of overcurrent, enhancing user satisfaction by stabilizing the washer's operation during repeated forward and reverse rotations.
Implementation Method 1
a speed/position detector for detecting the current speed and an current position of the rotor using an on/off signal of a hall sensor installed on the stator
Implementation Method 2
a motor controller performing a vector control method for controlling a current vector applied on a d-q axis rotating coordinate system
Implementation Method 3
a rotor having a plurality of permanent magnets spaced apart from the coils by a predetermined distance
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A motor, and a method and apparatus for controlling the motor for a washer are provided. The motor includes a stator on which a plurality of coils are wound and disposed in a circular shape, a rotor having a plurality of permanent magnets spaced apart from the coils by a predetermined distance, and a motor controller performing a vector control method for controlling a current vector applied on a d-q axis rotating coordinate system in a start mode of the rotor to make a current speed of the rotor follow a reference speed of the rotor by comparing the current speed with the reference speed. The motor controller includes a speed/position detector for detecting the current speed and a current position of the rotor using an on/off signal of a hall sensor installed on the stator.